Cover plate assembly



Feb. 26,1957

R. H. BOARDMAN 2,782,960

COVER PLATE ASSEMBLY Filed Jan. 15, 1954 INVENTOR. PAY/40MB H BOA F'DMAN A T OPNEYS United States Patent COVER PLATE ASSEMBLY Raymond H. Boardman, Hartford, Conn., assignor to The Hart Manufacturing Company, Hartford, Conn., a corporation of Connecticut Application January 15, 1954, Serial No. 404,208

4 Claims. (Cl. 220-60) This invention relates generally to closure members and pertains more particularly to a cover plate for switch boxes and the like.

One important object of the invention is to provide a cover plate which is not susceptible to accidental or inadvertent detachment from the box to which it is fastened.

Another object of the invention is to provide a cover plate that may be fabricated inexpensively from relatively thin sheet metal, and, even though of relatively thin and flexible material, it will be assured of having each corner thereof firmly retained against the box to which it is attached.

A further object of the invention is to provide a cover plate of the foregoing type which is of one piece construction requiring no screws or auxiliary means to effect its attachment to the box with which it is designed to cover.

A still further purpose of the invention is to provide a cover plate which may be readily attached and detached when desired.

Yet another object of the invention resides in the provision of means for assuring the proper orientation of the cover plate relative to the box on which it is installed.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which'will be indicated in the appended claims.

In the drawing:

Figure 1 is an exploded perspective view showing the manner in which the cover plate is installed upon a switch box;

Figure 2 is a side elevational view with the cover plate in a covering position before the arms have been latched in place;

Figure 3 is a front elevational view corresponding to Figure 2;

Figure 4 is a side view similar to Figure 2 but with the arms latched; and,

Figure 5 is a front elevational view corresponding to Figure 4.

Referring in detail to the drawing, a cover plate designated in general by the reference numeral is fabricated from relatively thin sheet metal, the cover plate including a panel 12 which may bulge or relieve outwardly to provide added rigidity to said panel. Also, included as elements of the cover plate are a plurality of flat resilient latch arms 14, 16, 18, and 20, each comprising a horizontal straight portion 22, an elbow 24, a vertical straight portion 26, and a finger 28 carried at the extremity of the straight portion 26. These resilient arms are preferably integral with the panel 12, and nor mally reside in parallel planes which are substantially at right angles to the general plane of the panel 12. As will be clearly seen from the drawing, each arm 14, 16,

2,782,960 Patented Feb. 26, 1957 "ice 18, and 20 is appreciably wider than it is thick thereby permitting ready deflection of the arms in a plane parallel to thatvof the panel 12 but providing appreciable resistance to any deflection in a plane normal to the plane of the panel 12.

The cover plate 10 is intended to cooperate with a box 30, which box is illustrated as an electrical switch box and which may be of plastic construction to afford insulation for the various switch elements housed therein, having laterally projecting lugs or protuberances 32 and 34. These lugs are each equipped with a shoulder or abutment 36 and an inclined or tapered face 38 for purposes presently to be explained. Also forming a part of the switch box 30 is a forwardly projecting key 40 at its upper edge and a 'second projecting key 42 at its lower edge, the latter key being of greater width than the former. Cooperating with the lugs 32, 34, and the keys 40, 42 is plurality of notched keyways 44, 46, 48, and 50 provided in the margins of the panel 12, said keyways being of sufficient width to clear the respective lugs and keys. By reason of the differences in widths of the keys 40 and 42, it will be seen that the keyways 48 and 50, complemental with the keys 40 and 42, permit the attachment of the cover plate 10 in only one oriented position relative to the box 30. As is conventional with switch boxes of this character, a switch shaft 52 for selecting particular switch contacts within the box is provided, there being a spring 54 for retaining an undisclosed turning knob in place upon said shaft 52 for the purpose of rotating said shaft into a desired angular position. To permit extension of the shaft 52 through the cover plate, there is providedan externally threaded bushing 56 which is carried at substantially the center of the panel 12 and which may'serveas the mounting means for the box structure.

In attaching the cover plate 10 to the switch box 30 the cover plate is manually held in the manner depicted in Figure 1 and movement of the cover plate toward the box results in the entrance of the shaft 52 into the bushing 56. Further movement of the cover plate 10 toward the box 30 results in the arms 14, 16, 18, and 20 straddling the sides of the box, the tapered surfaces 38 wedging the fingers 28 and thus the arms outwardly to permit the marginal edges of the panel 12 to abut against the foremost edge of the box 30 with the foremost portions of the lugs 32 and 34 engaging the notches 44 and 46 and with the keys 40 and 42 similarly engaging the notches 48 and 50.

The position assumed by the arms 14, 16, 18, and 20 at this particular stage is depicted in Figures 2 and 3. As shown in these figures the fingers 28 of the arms are in confronting engagement with one side of the lugs 32 and 34. To obtain a locking engagement between the fingers 28 and the shoulder or abutment 36 of each laterally projecting lug, it is necessary to force the fingers rearwardly to the extent that they may be deflected into the desired abutting or latching relationship with the shoulders 36. This relationship is clearly shown in Figures 4 and 5. It will be understood that any suitable implement may be used for urging the arms in a rearward direction so as to deflect said arms sufficiently to effect the desired latching engagement between the fingers 28 and said shoulders 36. Inasmuch as the arms 14, 16, 18, and 20 are relatively wide, although quite thin, they provide considerable resistance to deflection in a plane normal to the plane of the panel 12, but since they are relatively thin they may be later-ally deflected quite easily, little resistance being encountered to such lateral deflection. In this way, the removal of the cover plate 10 is precluded until the fingers 28 have been deflected outwardly from the sides of the box 30, such deflection outwardly returning the arms to the positions illustrated in Figures .2 and 3. After the arms have assumed this position, it will be seen that the cover plate may be readily withdrawn, the fingers sliding along the lugs 32 and 34 until complete separation has been accomplished.

In conclusion, it is thought apparent that the invention envisages the utilization of a cover plate which can be stamped and formed from relatively thin sheet metal, and even though such sheet metal has a natural tendency toward deflection in the general plane thereof, any such deflection or distortion of the panel 12 is precluded when installed on the box 30 by virtue of the arms 14, 16, 18, and 20 which are integrally joined with the panel adjacent its corners and which arms cooperate with the lugs 32 and 34 to retain the four corners of the panel 12 tightly against the corresponding corners of the switch box 30. Also, it will be recognized that the cover plate 10 is easily installed upon a box structure without the aid of threaded or other complex fastening means which require an appreciable amount of time in both attaching and detaching the cover plate. Further, once the cover plate has been properly positioned against the box 30, its removal will not accidentally occur, it being necessary to first deflect the arms laterally in order to disengage them from the lugs 32 and 34 before such removal is possible. Of course, the cover plate 10 will find considerable utility wherever it is desired to close an openended box structure, but for purposes of explanation, the box has herein been shown and described as a rotary switch :box.

As many changes could be made in the above construction and many apparently widely difierent embodiments of this invention could be made without departing from the scope thereof, .it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in thefollowing claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

I. In the combination of "an open-ended rectangular box and a cover therefor, a pair of substantially opposite and centrally disposed lateral projections on said lbox,

each of said lateral projections having .a forwardly and inwardly inclined cam surface and a rearwardly facing shoulder, two pairs of flat resilient L-shaped arms integral with said cover and disposed adjacent the corners thereof, each of said arms having a rearwardly extending relatively short shank portion and a relatively long intermediate portion disposed parallel to a side edge of the cover, the free ends of said intermediate portions being adapted to cam over said projections and underlie the rearwardly facing shoulders thereof.

2. A one-piece sheet metal detachable cover for an open-ended box structure comprising a generally rectangular relatively thin panel, a pair of flat L-shaped resilient arms extending integrally from each side edge of said panel adjacent the ends thereof and in a plane perpendicular to said panel, each of said arms having a relatively short wide shank disposed substantially perpendicular to the side edge of the panel and a relatively long narrow intermediate portion disposed parallel to the side edge of the panel, and a finger on each of said arms arranged to engage a centrally disposed projection on :the side of the box structure.

3. In combination, an open-ended box structure having laterally extending projections, each of said laterally extending projections having a forwardly and inwardly inclined cam surface and a rearwardly facing shoulder, and a cover plate of relatively thin sheet material including a generally rectangular panel provided with two pairs of flat resilient L-shaped arms integrally extending from said panel adjacent the corners thereof and bent at substantially right angles to the plane thereof, the arms of each pair having relatively short shank portions gen erally perpendicular to the side edges ,of said panel and oppositely extending relatively long portions generally parallel'to the side edges of said panel and tapering to.- Ward their free ends, and fingers on the free ends of the taperedportions extending into engagement with the rearwardly facin g shoulders of said projections.

4. The combination in accordance with claim 3 in which said box structure is provided with a pair of forwardly extending keys of diflerent widths and said cover plateis provided with notched complemental keyways to .avssure the proper orientation of said plate relative to said box structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,433,587 'WentWorth Dec. 30, 1947 2,454,455 Irwin Nov. 23, 1948 2,665,353 Popp Jan. 5, 1954 

